US4769968A - Truss-core corrugation for compressive loads - Google Patents

Truss-core corrugation for compressive loads Download PDF

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Publication number
US4769968A
US4769968A US07/022,298 US2229887A US4769968A US 4769968 A US4769968 A US 4769968A US 2229887 A US2229887 A US 2229887A US 4769968 A US4769968 A US 4769968A
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United States
Prior art keywords
truss
corrugated
section
cap strips
panel structure
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Expired - Fee Related
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US07/022,298
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Randall C. Davis
L. Robert Jackson
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National Aeronautics and Space Administration NASA
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National Aeronautics and Space Administration NASA
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Priority to US07/022,298 priority Critical patent/US4769968A/en
Assigned to UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION reassignment UNITED STATES OF AMERICA, THE, AS REPRESENTED BY THE ADMINISTRATOR OF THE NATIONAL AERONAUTICS AND SPACE ADMINISTRATION ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: DAVIS, RANDALL C., JACKSON, L. ROBERT
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
    • B64C1/06—Frames; Stringers; Longerons ; Fuselage sections
    • B64C1/12—Construction or attachment of skin panels
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
    • E04C2/32—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure formed of corrugated or otherwise indented sheet-like material; composed of such layers with or without layers of flat sheet-like material
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
    • E04C2/34—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts
    • E04C2/3405—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by profiled spacer sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
    • B64C2001/0054—Fuselage structures substantially made from particular materials
    • B64C2001/0072—Fuselage structures substantially made from particular materials from composite materials
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B64—AIRCRAFT; AVIATION; COSMONAUTICS
    • B64C—AEROPLANES; HELICOPTERS
    • B64C1/00—Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like
    • B64C2001/0054—Fuselage structures substantially made from particular materials
    • B64C2001/0081—Fuselage structures substantially made from particular materials from metallic materials
    • E—FIXED CONSTRUCTIONS
    • E04—BUILDING
    • E04C—STRUCTURAL ELEMENTS; BUILDING MATERIALS
    • E04C2/00—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels
    • E04C2/30—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure
    • E04C2/34—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts
    • E04C2/3405—Building elements of relatively thin form for the construction of parts of buildings, e.g. sheet materials, slabs, or panels characterised by the shape or structure composed of two or more spaced sheet-like parts spaced apart by profiled spacer sheets
    • E04C2002/3444—Corrugated sheets
    • E04C2002/345—Corrugated sheets with triangular corrugations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T50/00—Aeronautics or air transport
    • Y02T50/40—Weight reduction
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
    • Y10T428/24628—Nonplanar uniform thickness material
    • Y10T428/24669—Aligned or parallel nonplanarities
    • Y10T428/24694—Parallel corrugations

Definitions

  • the present invention relates to a structure for supporting compressive loads with a high strength-to-weight efficiency and, more particularly, to a structure which can be used in the fuselage of a rocket or aircraft or to form fuel tanks.
  • FIGS. 1-3 illustrate a corrugated panel construction.
  • This structure is illustrated in FIGS. 1-3 and includes beaded-web corrugation 20 bonded to cap strips 22 at uncorrugated regions or "flats" 24 at bond lines 26 (FIG. 2).
  • the corrugated portion of the beaded web 20 has an undulating or sinusoidal cross-section.
  • the beaded web 20 is typically superplastic formed of very thin sheets with concurrent diffusion bonding (SPF/DB) to the curved cap strips 22.
  • SPPF/DB diffusion bonding
  • the SPF/DB method of fabrication utilizes two inherent phenomena which tend to occur concurrently in, e.g., titanium alloys.
  • the first phenomenon is the ability of a material, such as titanium alloy, to undergo large, up to 1,000 percent strain, plastic deformations at high temperatures without localized thinning, or necking. This phenomenon often is referred to as superplasticity.
  • the second phenomenon relates to the capability of being joined under pressures at elevated temperatures, without melting or the use of bonding agents, which is referred to as diffusion bonding.
  • the corrugation structure illustrated in FIG. 1 may have an overall thickness of two to three (2-3) inches from the top of a curved cap 22 on one side to the top of another cap 22 curved in the opposite direction.
  • the beaded-web 20 and cap strip 22 may have thicknesses of two to five (2-5) mil and thirty to sixty (30-60) mil, respectively. Since FIGS. 1-3 are approximately to scale for the above "optimized design", a good approximation for other dimensions can be obtained from FIGS. 1-3.
  • the beaded-web material 20 accounts for two-thirds of the total structural mass.
  • the web material 20 is beaded so that it provides a load carrying capacity in a direction perpendicular to the compressive load and the "flats" to which the cap strips 22 are bonded are so thin they provide an insignificant amount of load carrying capability. Consequently, 67% of a beaded-web, curved-cap corrugation structure, constructed as described above, carries very little of the compressive load.
  • the compressive loading is limiting, there is considerable inefficiency and limiting, there is considerable inefficiency and potential room for improvement.
  • the cap strips 22 carry the compressive load.
  • the thickness-to-width ratio and the edge restraint of the cap strips 22 determine the ability of the cap strips 22 to resist local buckling.
  • the beading in the web 20 helps prevent local buckling in the web 20 while allowing maximum separation between the strips 22.
  • the separation between the cap strips determines the stiffness of the corrugation structure to resist overall buckling.
  • the bead depth d (FIG. 1) helps provide edge restraint for the cap strips 22, but introduces load discontinuities due to the variation in the amount of the cap strip 22 which is supported by the beaded web 20.
  • An object of the present invention is to provide a structure for a compressive loading limited application having a high strength-to-weight structural efficiency.
  • a further object of the present invention is to provide a cap-web corrugated panel in which the web portion of the panel is load carrying.
  • Another object of the present invention is to provide a cap-web corrugated panel having caps with high local buckling strength.
  • a further object of the present invention is to provide a cap-web corrugated panel with no load discontinuities.
  • An additional object of the present invention is to provide a cap-web corrugated panel in which the web segments provide a continuous straight support for the edges of the caps.
  • a corrugated panel structure for supporting a compressive load in a length direction, comprising cap strips, extending in the length direction and having a curved cross-section, and truss-core web segments, bonded to and separating the cap strips, each truss-core web segment having a sandwich construction and including first and second flat panels parallel to the length direction and a corrugated filler, bonded between the first and second flat panels, extending in the length direction with a non-linear cross-section.
  • first and second flat panels of the truss-core web segment are offset in a width direction perpendicular to the length direction, thereby forming a first extension of the first flat panel which extends beyond the second flat panel at one side of the truss-core web segment and a second extension of the second flat panel which extends beyond the first flat panel on an opposite side of the truss-core web segment.
  • the first and second panels each include a flange, formed on one of the first and second extensions, for bonding to the cap strips.
  • the cap strips are preferably convex, i.e., formed with a first side bonded to the truss-core web segments and with the curved cross-section of each of the cap strips forming an apex on a second side opposite the first side.
  • a slight amount of structural strength can be traded for increased damage resistance by forming concave cap strips, i.e., so that each of the cap strips has an apex between two of the truss-core segments.
  • cap strips With concave cap strips, increased rotational stability of the cap strips can be provided by crimping the cap strips to form third and fourth extensions on each of the cap strips, each of the third and fourth extensions bonding to the outside of one of the first and second panels of one of the truss-core web segments, where the inside of the first and second panels is bonded to the corrugated filler.
  • FIG. 1 is a perspective view of a prior art beaded-web corrugated panel
  • FIG. 2 is a cross-section view, taken along line 2--2 of FIG. 1, illustrating the bonding of the edge of a cap strip beaded-web corrugation in the prior art;
  • FIG. 3 is a cross-section view, taken along line 3--3 in Fi 1 illustrating the beaded-web in the prior art
  • FIG. 4 is a perspective view of a corrugated panel according present invention.
  • FIG. 5 is a perspective view of a single truss-core web segment used in a corrugated panel according to the present invention.
  • FIG. 6 is a plot of structural efficiency curves for two prior art structures and two truss-core corrugations according to the present invention.
  • FIG. 7 is a perspective view of a straight section of a corrugated panel according to a first embodiment of the present invention.
  • FIG. 8 is a perspective view of a straight section of a corrugated panel according to a second embodiment of the present invention.
  • the curved cap 22 is supported by a truss-core web segment 30 instead of the beaded web 20.
  • the truss-core web segment 30 is formed from an inner flat panel 32 which is separated from an outer flat panel 34 by a corrugated filler 36.
  • the corrugations in the filler 36 extend in the direction of loading and thus are capable of carrying part of the compressive load.
  • the corrugated filler 36 may have a substantially saw-tooth cross-section, as illustrated in FIG. 5 or a more sinusoidal cross-section.
  • each truss-core web segment 30 is preferably offset in the width direction (perpendicular to the length direction of the compressive load), so that each panel has an extension 37 extending beyond the adjacent panel.
  • Each of the extensions 37 joins a cap strip 22 at a flange 38 on a side of the cap strip 22 which is opposite the apex 39.
  • the truss-core web segment 30 provides rotational restraint for the cap 22 without any load discontinuities as in the prior art beaded-web, curved-cap structure illustrated in FIG. 1.
  • the truss-core web 30 provides significantly more stiffness to support the edges of the cap strips 22, thus greatly improving the local buckling strength of the caps 22.
  • FIG. 6 compares the strength-to-weight efficiency of various panel constructions under compressive loading on a log-log graph.
  • the ordinate is a mass coefficient t/L, where t is a mass equivalent thickness and L is the length of the span, e.g., 30 inches.
  • the abscissa is a strength coefficient N/EL which is determined for a panel with material modulus E transferring a compressive load per unit width N over a span of length L. The most efficient panel for a given load will have the lowest value of t/L.
  • the line “yield (0.008)" indicates the upper limit of a structure's load carrying ability without yielding or buckling.
  • truss-core corrugation structures have significantly lower mass coefficients for certain dimensions and load coefficients, compared to both beaded-web corrugation and a 1.5% honeycomb structure which is presently in use in some applications.
  • the truss-core corrugation structure illustrated in FIG. 4 can be repeated to form a structure of any desired width, or with gradual curvature to form a continuous cylindrical housing or shell such as that used in a fuselage or fuel tank.
  • a straight structure containing several cap strips 22 and truss-core segments 30 is illustrated in FIG. 7.
  • FIG. 8 illustrates a group of several modified cap strips 22' having a concave surface with an apex 39' between two truss-core segments 30, instead of the convex surface illustrated in FIGS. 4, 5 and 7.
  • the modified cap strips 22' include crimped edges forming extensions 40 which further stabilize the cap edges against rotation.
  • the concave curvature of the cap strips 22' improves the damage resistance of the structure, although slightly reducing the load capacity.
  • the structure illustrated in FIG. 8 would be used primarily where insufficient protection is provided by an outer skin surrounding the corrugation.
  • either or both of the truss-core web sections 30 and the metal cap strips 22 may be metallic, metallic with composite reinforcement or non-metallic materials, such as fibrous composite materials.

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  • Engineering & Computer Science (AREA)
  • Architecture (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Laminated Bodies (AREA)

Abstract

A corrugated panel structure for supporting compressive loads includes curved cap strips 22 separated by truss-core web segments 30. The truss-core web segments 30 are formed from first and second flat panels 32 and 34 with a corrugated filler 36 therebetween. The corrugated filler 36 extends in the direction of the compressive load, thereby providing load carrying capability for the compressive load. As a result, all components of the panel structure have a compressive load carrying capability resulting in a high strength-to-weight ratio when the compressive load is limiting.

Description

ORIGIN OF THE INVENTION
The invention described herein was made by employees of the United States Government and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefor.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure for supporting compressive loads with a high strength-to-weight efficiency and, more particularly, to a structure which can be used in the fuselage of a rocket or aircraft or to form fuel tanks.
2. Description of the Related Art
In applications where it is desirable for a structure to be as light as possible while withstanding relatively high loads, e.g., in an aircraft or rocket, many types of structures have been used. In the prior art, the highest efficiency structure for carrying a compressive load utilizes a corrugated panel construction. This structure is illustrated in FIGS. 1-3 and includes beaded-web corrugation 20 bonded to cap strips 22 at uncorrugated regions or "flats" 24 at bond lines 26 (FIG. 2). As illustrated in cross-section in FIG. 3, the corrugated portion of the beaded web 20 has an undulating or sinusoidal cross-section.
The beaded web 20 is typically superplastic formed of very thin sheets with concurrent diffusion bonding (SPF/DB) to the curved cap strips 22. As described in U.S. Pat. No. 4,292,375, the SPF/DB method of fabrication utilizes two inherent phenomena which tend to occur concurrently in, e.g., titanium alloys. The first phenomenon is the ability of a material, such as titanium alloy, to undergo large, up to 1,000 percent strain, plastic deformations at high temperatures without localized thinning, or necking. This phenomenon often is referred to as superplasticity. The second phenomenon relates to the capability of being joined under pressures at elevated temperatures, without melting or the use of bonding agents, which is referred to as diffusion bonding.
In an optimized design the corrugation structure illustrated in FIG. 1 may have an overall thickness of two to three (2-3) inches from the top of a curved cap 22 on one side to the top of another cap 22 curved in the opposite direction. The beaded-web 20 and cap strip 22 may have thicknesses of two to five (2-5) mil and thirty to sixty (30-60) mil, respectively. Since FIGS. 1-3 are approximately to scale for the above "optimized design", a good approximation for other dimensions can be obtained from FIGS. 1-3.
In this "optimized designs", the beaded-web material 20 accounts for two-thirds of the total structural mass. The web material 20 is beaded so that it provides a load carrying capacity in a direction perpendicular to the compressive load and the "flats" to which the cap strips 22 are bonded are so thin they provide an insignificant amount of load carrying capability. Consequently, 67% of a beaded-web, curved-cap corrugation structure, constructed as described above, carries very little of the compressive load. When the compressive loading is limiting, there is considerable inefficiency and limiting, there is considerable inefficiency and potential room for improvement.
In the beaded-web, curved-cap structure, the cap strips 22 carry the compressive load. The thickness-to-width ratio and the edge restraint of the cap strips 22 determine the ability of the cap strips 22 to resist local buckling. The beading in the web 20 helps prevent local buckling in the web 20 while allowing maximum separation between the strips 22. The separation between the cap strips determines the stiffness of the corrugation structure to resist overall buckling. The bead depth d (FIG. 1) helps provide edge restraint for the cap strips 22, but introduces load discontinuities due to the variation in the amount of the cap strip 22 which is supported by the beaded web 20.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a structure for a compressive loading limited application having a high strength-to-weight structural efficiency.
A further object of the present invention is to provide a cap-web corrugated panel in which the web portion of the panel is load carrying.
Another object of the present invention is to provide a cap-web corrugated panel having caps with high local buckling strength.
A further object of the present invention is to provide a cap-web corrugated panel with no load discontinuities.
An additional object of the present invention is to provide a cap-web corrugated panel in which the web segments provide a continuous straight support for the edges of the caps.
The above-mentioned objects are obtained by providing a corrugated panel structure for supporting a compressive load in a length direction, comprising cap strips, extending in the length direction and having a curved cross-section, and truss-core web segments, bonded to and separating the cap strips, each truss-core web segment having a sandwich construction and including first and second flat panels parallel to the length direction and a corrugated filler, bonded between the first and second flat panels, extending in the length direction with a non-linear cross-section.
In a preferred embodiment, the first and second flat panels of the truss-core web segment are offset in a width direction perpendicular to the length direction, thereby forming a first extension of the first flat panel which extends beyond the second flat panel at one side of the truss-core web segment and a second extension of the second flat panel which extends beyond the first flat panel on an opposite side of the truss-core web segment. In this embodiment, the first and second panels each include a flange, formed on one of the first and second extensions, for bonding to the cap strips. If maximum strength is desired and the corrugated panel is protected by, e.g., a heat shield, the cap strips are preferably convex, i.e., formed with a first side bonded to the truss-core web segments and with the curved cross-section of each of the cap strips forming an apex on a second side opposite the first side. A slight amount of structural strength can be traded for increased damage resistance by forming concave cap strips, i.e., so that each of the cap strips has an apex between two of the truss-core segments. With concave cap strips, increased rotational stability of the cap strips can be provided by crimping the cap strips to form third and fourth extensions on each of the cap strips, each of the third and fourth extensions bonding to the outside of one of the first and second panels of one of the truss-core web segments, where the inside of the first and second panels is bonded to the corrugated filler.
These objects, together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a prior art beaded-web corrugated panel;
FIG. 2 is a cross-section view, taken along line 2--2 of FIG. 1, illustrating the bonding of the edge of a cap strip beaded-web corrugation in the prior art;
FIG. 3 is a cross-section view, taken along line 3--3 in Fi 1 illustrating the beaded-web in the prior art;
FIG. 4 is a perspective view of a corrugated panel according present invention;
FIG. 5 is a perspective view of a single truss-core web segment used in a corrugated panel according to the present invention;
FIG. 6 is a plot of structural efficiency curves for two prior art structures and two truss-core corrugations according to the present invention;
FIG. 7 is a perspective view of a straight section of a corrugated panel according to a first embodiment of the present invention; and
FIG. 8 is a perspective view of a straight section of a corrugated panel according to a second embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIGS. 4 and 5, according to the present invention, the curved cap 22 is supported by a truss-core web segment 30 instead of the beaded web 20. As illustrated in FIG. 5, the truss-core web segment 30 is formed from an inner flat panel 32 which is separated from an outer flat panel 34 by a corrugated filler 36. As illustrated in FIG. 4, the corrugations in the filler 36 extend in the direction of loading and thus are capable of carrying part of the compressive load. The corrugated filler 36 may have a substantially saw-tooth cross-section, as illustrated in FIG. 5 or a more sinusoidal cross-section.
The flat panels 32 and 34 in each truss-core web segment 30 are preferably offset in the width direction (perpendicular to the length direction of the compressive load), so that each panel has an extension 37 extending beyond the adjacent panel. Each of the extensions 37 joins a cap strip 22 at a flange 38 on a side of the cap strip 22 which is opposite the apex 39. Thus, the truss-core web segment 30 provides rotational restraint for the cap 22 without any load discontinuities as in the prior art beaded-web, curved-cap structure illustrated in FIG. 1. The truss-core web 30 provides significantly more stiffness to support the edges of the cap strips 22, thus greatly improving the local buckling strength of the caps 22.
The significant advantages of the present invention over prior art structures are indicated in FIG. 6 which compares the strength-to-weight efficiency of various panel constructions under compressive loading on a log-log graph. The ordinate is a mass coefficient t/L, where t is a mass equivalent thickness and L is the length of the span, e.g., 30 inches. The abscissa is a strength coefficient N/EL which is determined for a panel with material modulus E transferring a compressive load per unit width N over a span of length L. The most efficient panel for a given load will have the lowest value of t/L. The line "yield (0.008)" indicates the upper limit of a structure's load carrying ability without yielding or buckling.
As depicted in FIG. 6, truss-core corrugation structures have significantly lower mass coefficients for certain dimensions and load coefficients, compared to both beaded-web corrugation and a 1.5% honeycomb structure which is presently in use in some applications. A truss-core corrugation structure with a truss-core depth (d) of 0.25 inches and a truss-core with flat panels and inner corrugation formed from foil with a thickness (tmg) of 0.005 inches (5 mil) has a lower mass coefficient than the beaded-web corrugation at higher loads, while the truss-core corrugation with d=0.125 inches and tmg=0.002 inches is substantially lower than the beaded-web corrugation over a wide range of loads.
The truss-core corrugation structure illustrated in FIG. 4 can be repeated to form a structure of any desired width, or with gradual curvature to form a continuous cylindrical housing or shell such as that used in a fuselage or fuel tank. A straight structure containing several cap strips 22 and truss-core segments 30 is illustrated in FIG. 7.
In addition, the cap strip 22 can be modified to provide additional stability. FIG. 8 illustrates a group of several modified cap strips 22' having a concave surface with an apex 39' between two truss-core segments 30, instead of the convex surface illustrated in FIGS. 4, 5 and 7. The modified cap strips 22' include crimped edges forming extensions 40 which further stabilize the cap edges against rotation. The concave curvature of the cap strips 22' improves the damage resistance of the structure, although slightly reducing the load capacity. Thus, the structure illustrated in FIG. 8 would be used primarily where insufficient protection is provided by an outer skin surrounding the corrugation.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to these skilled in the art, it is not desired to limit the invention to the exact construction and applications shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention and the appended claims and their equivalents. For example, either or both of the truss-core web sections 30 and the metal cap strips 22 may be metallic, metallic with composite reinforcement or non-metallic materials, such as fibrous composite materials.

Claims (11)

What is claimed is:
1. A corrugated panel structure for supporting a compressive load in a length direction, comprising: cap strips extending in the length direction, having a curved cross-section; and
truss-core web segments, bonded to and separating said cap strips in an open cross-section arrangement each truss-core web segment having a sandwich construction, including first and second flat panels parallel to the length direction and a corrugated filler, bonded between said first and second flat panels, extending in the length direction with a non-linear cross-section.
2. A corrugated panel structure as recited in claim 1, wherein said corrugated filler has a substantially saw-toothed cross-section.
3. A corrugated panel structure as recited in claim 1, wherein said corrugated filler has a substantially sinusoidal cross-section.
4. A corrugated panel structure as recited in claim 1, wherein said cap strips have a first side bonded to said truss-core web segments and the curved cross-section of each of said cap strips forms an apex on a second side opposite the first side.
5. A corrugated panel structure as recited in claim 1, wherein the cross-section of each of said cap strips has an apex formed between two of said truss-core segments.
6. A corrugated panel structure as recited in claim 1, wherein said first and second flat panels are offset in a width direction perpendicular to the length direction, said first flat panel thereby including a first extension extending beyond said second flat panel at one side of each of said truss-core web segments and said second flat panel including a second extension extending beyond said first flat panel at an opposite side of each of said truss-core web segments.
7. A corrugated panel structure as recited in claim 6,
wherein said first and second flat panels each have an inside and an outside, the inside being bonded to said corrugated filler, and
wherein each of said cap strips include third and fourth extensions, each bonding to the outside of one of said first and second panels of one of said truss-core web segments.
8. A corrugated panel structure as recited in claim 6, wherein said first and second panels each include a flange, formed on one of said first and second extensions of said first and second panels, for bonding to said cap strips.
9. A corrugated panel structure as recited in claim 8, wherein said cap strips have a first side bonded to said truss-core web segments and the curved cross-section of each of said cap strips forms an apex on a second side opposite the first side.
10. A corrugated panel structure as recited in claim 8, wherein the cross-section of each of said cap strips has an apex formed between two of said truss-core segments.
11. A corrugated panel structure for supporting a compressive load in a length direction, comprising:
cap strips extending in the length direction, having a curved cross-section with an apex; and
truss-core web segments, bonded to and separating said cap strips, the apex of the curved cross-section of each of said cap strips being formed between two of said truss-core web segments, each of said truss-core web segments having a sandwich construction, including first and second flat panels parallel to the length direction and a corrugated filler, bonded between said first and second flat panels, extending in the length direction with a non-linear cross-section.
US07/022,298 1987-03-05 1987-03-05 Truss-core corrugation for compressive loads Expired - Fee Related US4769968A (en)

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Cited By (43)

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FR2640540A1 (en) * 1988-12-21 1990-06-22 Stihl Andreas MASSIVE GUIDE BAR FOR THE SAWING CHAIN OF A CHAIN ENGINE SAW
US5348601A (en) * 1993-06-23 1994-09-20 The United States Of America As Represented By The Secretary Of The Navy Method of making an offset corrugated sandwich construction
US5424113A (en) * 1993-06-23 1995-06-13 The United States Of America As Represented By The Secretary Of The Navy Lattice core sandwich construction
USH1481H (en) * 1993-06-23 1995-09-05 The United States Of America As Represented By The Secretary Of The Navy Offset corrugated sandwich construction
US5535912A (en) * 1994-03-17 1996-07-16 A. O. Smith Corporation Metal liner for a fiber-reinforced plastic tank
USH1621H (en) * 1995-01-31 1996-12-03 The United States Of America As Represented By The Secretary Of The Navy Offset corrugated panel with curved corrugations for increased strength
US5598930A (en) * 1995-07-20 1997-02-04 Advanced Wirecloth, Inc. Shale shaker screen
US5971159A (en) 1993-04-30 1999-10-26 Tuboscope I/P, Inc. Screen assembly for a vibratory separator
US6029824A (en) * 1994-03-30 2000-02-29 Tuboscope I/P, Inc. Screen for vibrating separator
USD425531S (en) * 1999-03-29 2000-05-23 Tuboscope I/P, Inc. Screen
US6152307A (en) 1993-04-30 2000-11-28 Tuboscope I/P, Inc. Vibratory separator screens
US6267247B1 (en) 1993-04-30 2001-07-31 Tuboscope I/P, Inc. Vibratory separator screen
US6269953B1 (en) 1993-04-30 2001-08-07 Tuboscope I/P, Inc. Vibratory separator screen assemblies
US6283302B1 (en) 1993-08-12 2001-09-04 Tuboscope I/P, Inc. Unibody screen structure
US6290068B1 (en) 1993-04-30 2001-09-18 Tuboscope I/P, Inc. Shaker screens and methods of use
US6325216B1 (en) 1993-04-30 2001-12-04 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6371302B1 (en) 1993-04-30 2002-04-16 Tuboscope I/P, Inc. Vibratory separator screens
US6401934B1 (en) 1993-04-30 2002-06-11 Tuboscope I/P, Inc. Ramped screen & vibratory separator system
US6443310B1 (en) 1993-04-30 2002-09-03 Varco I/P, Inc. Seal screen structure
US6450345B1 (en) 1993-04-30 2002-09-17 Varco I/P, Inc. Glue pattern screens and methods of production
US6454099B1 (en) 1993-04-30 2002-09-24 Varco I/P, Inc Vibrator separator screens
US6565698B1 (en) 1993-04-30 2003-05-20 Varco I/P, Inc. Method for making vibratory separator screens
US6607080B2 (en) 1993-04-30 2003-08-19 Varco I/P, Inc. Screen assembly for vibratory separators
US6629610B1 (en) 1993-04-30 2003-10-07 Tuboscope I/P, Inc. Screen with ramps for vibratory separator system
US6669985B2 (en) 1998-10-30 2003-12-30 Varco I/P, Inc. Methods for making glued shale shaker screens
US6722504B2 (en) 1993-04-30 2004-04-20 Varco I/P, Inc. Vibratory separators and screens
US6736270B2 (en) 1998-10-30 2004-05-18 Varco I/P, Inc. Glued screens for shale shakers
US6932883B2 (en) 1998-10-30 2005-08-23 Varco I/P, Inc. Screens for vibratory separators
US7049548B1 (en) 2005-03-21 2006-05-23 The Boeing Company System and method for processing a preform vacuum vessel to produce a structural assembly
US20060210821A1 (en) * 2005-03-21 2006-09-21 The Boeing Company Method and apparatus for forming complex contour structural assemblies
US20090071098A1 (en) * 2007-09-14 2009-03-19 Ashton Larry J Reinforced composite panel
US7520391B2 (en) 1999-12-04 2009-04-21 Varco I/P, Inc. Screen assembly for vibratory separator
US20100011874A1 (en) * 2008-07-19 2010-01-21 The Boeing Company Method and apparatus for testing attachment joints
US20100186345A1 (en) * 2006-03-11 2010-07-29 Hughes Jr John P Ballistic construction panel
US20100308622A1 (en) * 2007-11-30 2010-12-09 Haruhiro Endo Hollow double-walled panel and interior panel for vehicle made using same
US20110042035A1 (en) * 2009-08-19 2011-02-24 Alstom Technology Ltd Heat transfer element for a rotary regenerative heat exchanger
US20120135200A1 (en) * 2010-11-29 2012-05-31 Burvill Thomas Aircraft panel structure and aircraft panel structure manufacturing method for alleviation of stress
US10094626B2 (en) 2015-10-07 2018-10-09 Arvos Ljungstrom Llc Alternating notch configuration for spacing heat transfer sheets
US10175006B2 (en) 2013-11-25 2019-01-08 Arvos Ljungstrom Llc Heat transfer elements for a closed channel rotary regenerative air preheater
US20190016483A1 (en) * 2017-06-28 2019-01-17 The Boeing Company Corrugated payload adaptor structure
US10197337B2 (en) 2009-05-08 2019-02-05 Arvos Ljungstrom Llc Heat transfer sheet for rotary regenerative heat exchanger
US10378829B2 (en) 2012-08-23 2019-08-13 Arvos Ljungstrom Llc Heat transfer assembly for rotary regenerative preheater
US10914527B2 (en) 2006-01-23 2021-02-09 Arvos Gmbh Tube bundle heat exchanger

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Cited By (62)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2640540A1 (en) * 1988-12-21 1990-06-22 Stihl Andreas MASSIVE GUIDE BAR FOR THE SAWING CHAIN OF A CHAIN ENGINE SAW
US6892888B2 (en) 1993-04-30 2005-05-17 Varco I/P, Inc. Screen with unibody structure
US6401934B1 (en) 1993-04-30 2002-06-11 Tuboscope I/P, Inc. Ramped screen & vibratory separator system
US6629610B1 (en) 1993-04-30 2003-10-07 Tuboscope I/P, Inc. Screen with ramps for vibratory separator system
US6607080B2 (en) 1993-04-30 2003-08-19 Varco I/P, Inc. Screen assembly for vibratory separators
US6565698B1 (en) 1993-04-30 2003-05-20 Varco I/P, Inc. Method for making vibratory separator screens
US6530483B2 (en) 1993-04-30 2003-03-11 Varco I/P, Inc. Unibody structure for screen assembly
US5971159A (en) 1993-04-30 1999-10-26 Tuboscope I/P, Inc. Screen assembly for a vibratory separator
US6454099B1 (en) 1993-04-30 2002-09-24 Varco I/P, Inc Vibrator separator screens
US6450345B1 (en) 1993-04-30 2002-09-17 Varco I/P, Inc. Glue pattern screens and methods of production
US6032806A (en) 1993-04-30 2000-03-07 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6443310B1 (en) 1993-04-30 2002-09-03 Varco I/P, Inc. Seal screen structure
US6152307A (en) 1993-04-30 2000-11-28 Tuboscope I/P, Inc. Vibratory separator screens
US6267247B1 (en) 1993-04-30 2001-07-31 Tuboscope I/P, Inc. Vibratory separator screen
US6269953B1 (en) 1993-04-30 2001-08-07 Tuboscope I/P, Inc. Vibratory separator screen assemblies
US6722504B2 (en) 1993-04-30 2004-04-20 Varco I/P, Inc. Vibratory separators and screens
US6290068B1 (en) 1993-04-30 2001-09-18 Tuboscope I/P, Inc. Shaker screens and methods of use
US6302276B1 (en) 1993-04-30 2001-10-16 Tuboscope I/P, Inc. Screen support strip for use in vibratory screening apparatus
US6325216B1 (en) 1993-04-30 2001-12-04 Tuboscope I/P, Inc. Screen apparatus for vibratory separator
US6371302B1 (en) 1993-04-30 2002-04-16 Tuboscope I/P, Inc. Vibratory separator screens
US5348601A (en) * 1993-06-23 1994-09-20 The United States Of America As Represented By The Secretary Of The Navy Method of making an offset corrugated sandwich construction
USH1481H (en) * 1993-06-23 1995-09-05 The United States Of America As Represented By The Secretary Of The Navy Offset corrugated sandwich construction
US5424113A (en) * 1993-06-23 1995-06-13 The United States Of America As Represented By The Secretary Of The Navy Lattice core sandwich construction
US6283302B1 (en) 1993-08-12 2001-09-04 Tuboscope I/P, Inc. Unibody screen structure
US5535912A (en) * 1994-03-17 1996-07-16 A. O. Smith Corporation Metal liner for a fiber-reinforced plastic tank
US6029824A (en) * 1994-03-30 2000-02-29 Tuboscope I/P, Inc. Screen for vibrating separator
USH1621H (en) * 1995-01-31 1996-12-03 The United States Of America As Represented By The Secretary Of The Navy Offset corrugated panel with curved corrugations for increased strength
US5598930A (en) * 1995-07-20 1997-02-04 Advanced Wirecloth, Inc. Shale shaker screen
US5988397A (en) 1996-02-12 1999-11-23 Tuboscope I/P, Inc. Screen for vibratory separator
US6736270B2 (en) 1998-10-30 2004-05-18 Varco I/P, Inc. Glued screens for shale shakers
US6932883B2 (en) 1998-10-30 2005-08-23 Varco I/P, Inc. Screens for vibratory separators
US6669985B2 (en) 1998-10-30 2003-12-30 Varco I/P, Inc. Methods for making glued shale shaker screens
USD425531S (en) * 1999-03-29 2000-05-23 Tuboscope I/P, Inc. Screen
US7520391B2 (en) 1999-12-04 2009-04-21 Varco I/P, Inc. Screen assembly for vibratory separator
US20060210821A1 (en) * 2005-03-21 2006-09-21 The Boeing Company Method and apparatus for forming complex contour structural assemblies
US7431196B2 (en) 2005-03-21 2008-10-07 The Boeing Company Method and apparatus for forming complex contour structural assemblies
US7049548B1 (en) 2005-03-21 2006-05-23 The Boeing Company System and method for processing a preform vacuum vessel to produce a structural assembly
US20080280156A1 (en) * 2005-03-21 2008-11-13 The Boeing Company Preform For Forming Complex Contour Structural Assemblies
US7866535B2 (en) 2005-03-21 2011-01-11 The Boeing Company Preform for forming complex contour structural assemblies
US10914527B2 (en) 2006-01-23 2021-02-09 Arvos Gmbh Tube bundle heat exchanger
US20100186345A1 (en) * 2006-03-11 2010-07-29 Hughes Jr John P Ballistic construction panel
US8544240B2 (en) * 2006-03-11 2013-10-01 John P. Hughes, Jr. Ballistic construction panel
US20090071098A1 (en) * 2007-09-14 2009-03-19 Ashton Larry J Reinforced composite panel
US8042315B2 (en) * 2007-09-14 2011-10-25 Spectrum Aeronautical, Llc Reinforced composite panel
US20100308622A1 (en) * 2007-11-30 2010-12-09 Haruhiro Endo Hollow double-walled panel and interior panel for vehicle made using same
US8376453B2 (en) * 2007-11-30 2013-02-19 Kyoraku Co., Ltd. Hollow double-walled panel and interior panel for vehicle made using same
US8286499B2 (en) * 2008-07-19 2012-10-16 The Boeing Company Method and apparatus for testing attachment joints
US8621935B2 (en) 2008-07-19 2014-01-07 The Boeing Company Method and apparatus for testing attachment joints
US20100011874A1 (en) * 2008-07-19 2010-01-21 The Boeing Company Method and apparatus for testing attachment joints
US10197337B2 (en) 2009-05-08 2019-02-05 Arvos Ljungstrom Llc Heat transfer sheet for rotary regenerative heat exchanger
US10982908B2 (en) 2009-05-08 2021-04-20 Arvos Ljungstrom Llc Heat transfer sheet for rotary regenerative heat exchanger
US8622115B2 (en) * 2009-08-19 2014-01-07 Alstom Technology Ltd Heat transfer element for a rotary regenerative heat exchanger
US9448015B2 (en) 2009-08-19 2016-09-20 Arvos Technology Limited Heat transfer element for a rotary regenerative heat exchanger
US20110042035A1 (en) * 2009-08-19 2011-02-24 Alstom Technology Ltd Heat transfer element for a rotary regenerative heat exchanger
US9145195B2 (en) * 2010-11-29 2015-09-29 Airbus Operations Limited Aircraft panel structure and aircraft panel structure manufacturing method for alleviation of stress
US20120135200A1 (en) * 2010-11-29 2012-05-31 Burvill Thomas Aircraft panel structure and aircraft panel structure manufacturing method for alleviation of stress
US10378829B2 (en) 2012-08-23 2019-08-13 Arvos Ljungstrom Llc Heat transfer assembly for rotary regenerative preheater
US11092387B2 (en) 2012-08-23 2021-08-17 Arvos Ljungstrom Llc Heat transfer assembly for rotary regenerative preheater
US10175006B2 (en) 2013-11-25 2019-01-08 Arvos Ljungstrom Llc Heat transfer elements for a closed channel rotary regenerative air preheater
US10094626B2 (en) 2015-10-07 2018-10-09 Arvos Ljungstrom Llc Alternating notch configuration for spacing heat transfer sheets
US20190016483A1 (en) * 2017-06-28 2019-01-17 The Boeing Company Corrugated payload adaptor structure
US10562650B2 (en) * 2017-06-28 2020-02-18 The Boeing Company Corrugated payload adaptor structure

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